import java.io.File;
import java.util.ArrayList;
import java.util.List;

public class test1 {

    public static void main(String[] args) {
        List<Character> now = new ArrayList<>();
        now.add('s');
        now.add('w');
        System.out.println(now);

//        File file = new File("D:\\JAVAw");
//        File[] children = file.listFiles();
//        System.out.println(children);
//        if(children == null){
//            System.out.println("我是空");
//        }
    }


}
